Alarm for locks



E. A. JARRETT ALARM FOR LOCKS Dec. 30, 1952 2 SHEETS--SHEET 1 Filed Sept. 25 1950 Fig. 2

Inventor Edwin A. Jarrett E- A. JARRETT ALARM FOR LOCKS Dec. 30, 1952 2 SHEETS-SHEET 2 Filed Sept. 25, 1950 Edwin A. Jarrett Patented Dec. 30, 1952 UNITED STATES PATENT OFFICE ALARM FOR LOCKS Edwin A. Jarrett, Suffern, N. Y.

Application September 25, 1950, Serial No. 186,608

2 Claims.

This invention comprises novel and useful improvements in switches, and more particularly pertains to a switch which is responsive to the positioning of a key in the lock.

An important object of this invention is to provide a switch which will be actuated whenever a key is positioned in the lock, whereby the switch may be utilized to actuate a signal to indicate that a key is positioned in the lock.

Another important object of this invention is to provide a switch which will be actuated whenever a key is positioned in the lock, which switch will remain actuated during the rotation of the lock barrel within the lock housing.

till another object of this invention is to provide a switch, in accordance with the foregoing object, which switch is compactly disposed in the lock housing, and operatively connected to one of the tumblers to be actuated thereby, whenever a key is positioned in the lock in engagement with the tumblers.

An important feature of this invention resides in the provision of a lock housing having a barrel rotatably mounted in the housing, and a plurality of tumblers movably mounted on the barrel, together with a contact terminal disposed in the lock housing, and a contact arm carried by one of the tumblers, which arm is engageable with the terminal whenever the tumblers are moved into their inoperative position by a key.

Another important feature of this invention resides in the provision of a lock housing having a barrel rotatably journaled therein, which barrel has a plurality of tumblers movably mounted thereon, together with a pair of arcuate contact terminals disposed in the housing, concentrically oi the barrel, with a contact arm carried by one of the tumblers, which contact arm engages the terminals whenever the tumblers are moved into their inoperative positions, and which switch will consequently maintain electrical contact independently of the angular position of the barrel with respect to the lock housing.

These, together with various ancillary objects and features are attained by this device, a preferred embodiment of which has been illustrated by way of example only in the accompanying drawings, wherein:

Figure 1 is a fragmentary longitudinal sectional view of the lock switch, with the tumblers shown in their locking positions;

Figure 2 is a fragmentary longitudinal sectional View of the lock switch, shown in Figure 1, with the tumblers moved'into their inoperative position, and with the switch arm shown bridging the electrical contact terminals;

Figure 3 is a transverse sectional view of the lock switch, taken substantially on the plane 33 of Figure 2;

Figure 4 is a schematic wiring diagram showing the manner in which the lock switch is connected to a signal to actuate the latter whenever a key is positioned within the lock;

Figure 5 is a fragmentary longitudinal sectional view of a second embodiment of the lock switch;

Figure 6 is a fragmentary longitudinal sectional view of the lock switch, shown in Figure 5, with the tumblers shown moved into their inoperative position by a key, and with the switch shown bridging the electrical contacts;

Figure 7 is a transverse sectional view, taken substantially on the plane 'I--'! of Figure 6; and

Figure 8 is a bottom plan view of the tumbler carrying the electrical contact arm.

Reference is now made more specifically to the accompanying drawings wherein like numerals designate similar parts throughout the various views, and in which a lock mechanism, indicated generally by the numeral [0 is provided with a switch mechanism, indicated generally by the numeral l2.

The lock mechanism HI, utilized in both embodiments of the lock switches shown in the accompanying drawings, is substantially the same, and includes a housing 14 having a bore 16 therein, and a counterbore l8 and an annular radial shoulder 20 between the bore and the counterbore. A cylindrical barrel 22 is provided with a longitudinally extending opening 24, and a plurality of transverse slots 26 which com-. municate with the opening 24, a plurality of tumblers 28 being reciprocably disposed within the slots 26. Each of the tumblers 28 is provided with an ear 30 which is receivable within a slot 32 in the barrel 22, whereby reciprocable movement of the tumblers relative to the barrel is limited. The tumblers 28 are also provided with a transverse lug 34 which is adapted to engage a spring 36, which spring otherwise engages the barrel 22, whereby the tumblers are yieldingly urged transversely of the barrel, and into locking position.

The housing I4 is also provided with a pair of longitudinally extending arcuate recesses 38 and 49, which recesses communicate with the bore [5, as is apparent from a consideration of Figures 1, 2, 5 and 6, and which recesses are of a length less than that of the bore IS, the inner ends of the recesses 38 and 40 terminating in spaced relation to the annular shoulder 22. A transversely movable key 42 is slidably mounted upon the barrel 22, as by the guideway 44, the key 42 being biased, as by a spring or the like into the position shown in Figures 1, 2, 5 and 6, wherein the key abuts the shoulder 22 to prevent outward movement of the barrel 22 relative to the housing [4. The outer end of the barrel 22 is provided with an annular rim 46 which is adapted to engage the outer end 48 of the housing It, to thereby li'n'iit inward movement of the barrel relative to the housing. As is shown clearly in the accompanying drawings, an internally threaded gland 50 rotatably embraces the rim 4B, the gland 50 further serving to detachably lock the housing It to a supporting surface 52, in conjunction with a suitable locknut 54.

Each of the tumblers 28 is provided witha central opening 56 through which a key 58 is adapted to extend, the sizes of the openings in the. various tumblers varying, as is clearly apparentifrom a consideration of the accompanying drawings, whereby when the key 58 is positioned within the barrel 22, and in engagement with the tumblers 28, the latter will be disposed, as is shown in Figures 2 and 6 with the outer. edgesthereof coincident with the outer surface of the barrel 22. However, when the key 58 is removed, the tumblers assume the position shown in Figures land 5, the tumblers 28 extending into'the recesses 38 whereby rotary motion of the barrel 22 relative to the housing I 4 is prevented.

The structure thus far described is conventional, and has been set forth merely as environment for the switch mechanism, to be described more fully hereinafter, which switch mechanism is actuated in response to movement of the tumblers into their inoperative position.

In the switch mechanism, shown in Figures 1 through 4, one of the tumblers 28 isformed of an electrically insulating material, as is shown in Figures 1 and 2, which tumbler is provided with a U-shaped channel member 6!] adjacent the lower portion of the opening 56, which channel member provides a wear plate for the toothed edge of the key 58. A plate 62 is secured, as by fasteners 64 to the upper end of the tumbler 25 which is formed of electrically, insulating material, which plate carries an oifset contact arm 66. A first and a second arcuate" contact terminal 68 and 10, respectively, are each embedded in an arcuate contact block 12, which block is disposed within the recess 38, adjacent the inner end thereof, with the contact terminals 68 and 7E] spaced radially from the barrel 22. First and second electrical conductors 14' and 76 are housed in electrically insulated sheaths 18, which conductors extend through bores 86 in the housing M, and which are terminally connected to the contact terminals 68 and 10, respectively. As will be appreciated from a consideration of Figure l, the spring 38 yieldinglyurges the electrically insulated contact arm 66 intothe position shown in Figure 1, in which position the arm does not contact both theterminals 68 and 76. However, when a key such as 58 is inserted in the barrel 22, the arm 66 is reciprocated downwardly into the position shown in Figure 2, thereby establishing contact between the terminals 68 and 19. It is intended that one of the conductors such as #5 be connected to a suitable source of power 82,, the other conductor 14 beingvelectrically connected to an alarm 84, which may be of the audio or visual type. From the foregoing; it Will be ap- 4 preciated that whenever a key is inserted in the barrel 22, that the alarm 84 will be actuated, and consequently indicate that a key is positioned within the lock. Since there are provided arcuate contact terminals 68 and 10, it will be appreciated that the arm 66 will maintain electrical contact, independently of the angular position of the barrel 22 relative to the housing [4.

In the second embodiment of the switch, shown in Figures 5 through 8, one of the tumblers 28 is also formed of electrically insulatedmaterial, which tumbler carries a U-shaped channel member 8t, to provide a wear plate for the key 58. The housing I4 is provided with a radial opening 88 in which is disposed a block 90, of electrically insulating material, which block has an inner surface 92 of arcuate contour, which surface isdisposed'concentric with the barrel 22, as is clearly shown in Figure 7. A first and a second contact terminal 9 3 and 96 are disposed in the block 98, andspaced longitudinally of the bore N5. in. the housing' l4, the inner' faces of which contact terminals being" disposed flush with the arcuate inner surface 92 of the block 99. The

I lower. end of the electrically insulated'tumbler 28 has a plate 98 secured thereto, by means of fasteners mo, which plate has a contact arm m2 secured thereto; and extending longitudinally of the housing Mgwhich. contact arm is adapted to bridge the terminals 95. and 95, in a manner clearly apparent from a' consideration of Figure 6. As'is more clearly apparent from a consideration of Figure 8, the plate 98 and arm IE2 may be formed: of asingle piece; of material.

The terminals 94. and 96 are respectively connected to conductors IE4 and [95, which are disposed in the electrically insulating sheaths I08, the conductor I04 being electrically connected to a suitable alarm I I0, of the audio or visual type, the conductor I06 being connected to a suitable source of power I [2.

As will be appreciated from the foregoing, the contact arm I02 will be moved into engagement withthe terminals 94 and 96 whenever a key 58 is inserted in the barrel 22', and since the inner sur faces of the contact terminals are arcuate, and disposed concentric withthe barrel, it will be appreciated that electrical contact will be maintained during: relative rotary motion between the barrel and the housing I4. It is further thought apparent that the switch unit [2, in the embodiment shown in Figures 5 through 8, in no way impairs the locking function of the electrically insulating tumbler 28, since the switch arm is connectedto the lower end of the tumbler.

From the foregoing, it isthought that the operation and construction of the device will be readily understood, and further description is therefore believed to be unnecessary. However, since numerous modifications will readily occur to those skilled in the art after a consideration of the foregoing specification and accompanying drawing, it is not intended to limit the invention to that shown and described, but all suitable modifications may be resorted to falling within the scope of the appended claims.

Having described the invention, what is claimed as new is:

1. A combined lock and switch for controlling an annunciator circuit, annunciating the presence of a key in the lock comprising a rotatable tumbler cylinder rotated by manual operation of said key with radially movable locking tumblers, moved by the insertion of the key, a non-locking tumbler of insulating material carrying a bridgder moved by the key, means for connecting said arcuate contact strips with the annunciator circuit, said bridging contact member being of a length adapted to bridge and connect the two spaced contact strips, and biasing means holding normally said bridging contact radially spaced from said arcuate contact, said bridging contact when radially moved towards the spaced contact strips by the insertion of a key remaining in contact with'the said strips in all positions of the key and tumbler cylinder.

2. A combined barrel-type tumbler lock and switch with a barrel enclosing a rotatable tumbler cylinder rotated upon insertion and turning of a proper key through a predetermined arc, said tumbler cylinder having a number of biased looking tumblers radially movable within said tumbler cylinder by the insertion of a key, said locking tumblers normally locking said tumbler cylinder against rotation until moved into non-locking position by the insertion of a proper key, whereupon the tumbler cylinder is rotatable by the said key through a predetermined arc comprising an additional radially movable biased non-locking tumbler of insulating material within said tumbler cylinder carrying a contact member, the radial position of which is changed by the insertion of the key, an insulating block member within said barrel and spaced strip-like arcuate contact segment carried by and held within said block, the arcuate contact segment being concentric with the tumbler cylinder and of a length substantially equal to the predetermined arc through which the key and tumbler cylinder is rotated, the contact member carried by the insulating non-locking tumbler member being of a length bridging the spaced contact segment carried by the block, and contact terminals on said barrel adapted to be connected with a circuit controlled by the combined lock and switch, the said bridging contact member carried by the tumbler being normally radially spaced from the arcuate contact segment in the insulating contact block and upon insertion of the properkey being radially moved 7 into a position of contact, bridging the arcuate contact segment, and maintaining this position during the rotation of the key and tumbler cylinder during which the said tumbler contact member slides in the strip-like arcuate contact segment.

EDWIN A. JARRETT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,057,301 Golokow Oct. 13, 1936 2,519,940 Smith Aug. 22, 1950 FOREIGN PATENTS Number Country Date 368,555 Germany Feb. 6, 1923 

